Automatic prediction of whether a customer will come into the shop or not
This should be possible, but it's not completely clear what you are trying to do.

If you're trying to predict customer age and gender from a video, then you've got a computer vision problem. Deep learning methods are the state of the art for this, and probably some sort of convolutional deep neural network is your friend. 

If you're trying to predict whether the customer will enter the shop from their age and gender, then @DuttA suggestion to start with simple classification techniques is probably the best bet. Try out logistic regression as a starting point. 

If you really want to do both of these things at once, you can again try out a deep convolutional neural network. 

All that said, it's not completely clear that there is signal in the videos you want to collect: it might be that predicting whether they'll enter the shop is not really possible on the basis of a short video. The only way to know for sure is to give it a try however.